There are several forms of radiation shielding doors that have been used to close doorways of rooms containing apparatus or materials which produce dangerous radiation, such as nuclear plants and cyclotron buildings.
One form of prior construction involves massive concrete doors which are movable in a direction perpendicular to the wall containing the doorway, moved by a large apparatus on the floor pulling the door outward from the doorway and subsequently pushing the door back into the doorway, as the door moves on large railway wheels, and riding on railway tracks mounted on the floor, or flush with the floor.
The above type of radiation shielding door has several undesirable aspects. Although this perpendicularly traveling door is advantageous in that it moves into and fills the doorway in a wall as well as overlapping a portion of the wall around the doorway, the door is located in an undesirable place, straight out in front of the doorway, when it is opened, requiring travel into and out of the doorway to proceed around the side of the door. The railway tracks located under the door and the pocket in the door for containing the wheel form paths for radiation leakage under the door. Railway tracks in the doorway pose a potential problem with some forms of movement through the open doorway. The large apparatus for moving a door wasted a substantial amount of valuable floor space.